The invention relates to an electro-optic Mach-Zehnder modulator arrangement and to a method for operating a Mach-Zehnder modulator arrangement.
It is known in the art to use Mach-Zehnder interferometers as electro-optic modulators in optical high-speed transmission systems, wherein, for example, separate (electrically uncoupled) continuous electrodes disposed on the optical waveguides of the modulator are employed for applying a voltage across the optical waveguides. Such a modulator is disclosed, for example, in the publication “Advances in InP Mach-Zehnder modulators for large capacity photonic network systems”, H. Yasaka et al., Indium Phosphide and Related Materials, IPRM 2008, p. 1. A high frequency (e.g. >20 GHz) voltage is supplied to the electrodes by two 50 Ohm drivers amplifying a high frequency input signal. The optical waveguides comprise capacitive segments in the form of integrated diodes, wherein a DC bias is applied to the electrodes in order to bias the diodes in reverse direction. In order to prevent the DC voltage from entering the drivers, a DC blocking capacitance or a bias-T has to be arranged between the output ports of the drivers and the electrodes of the modulator. The DC blocking capacitance or the bias-T, however, may deteriorate the high frequency properties of the modulator and incurs additional costs.
Further, the publication “10 Gb/s-80-km operation of full C-band InP MZ modulator with linear-accelerator-type tiny in-line centipede electrode structure directly driven by logic IC of 90-nm CMOS process”, T. Kato et al., Optical Fiber Communication Conference and Exposition, 2011, p. 1, discloses a Mach-Zehnder modulator comprising a plurality of waveguide electrodes arranged on the optical waveguides of the modulator, wherein multiple drivers are used to individually drive the waveguide electrodes.